Means for producing electrical oscillations.



GEORG GRAF ARGO 81 RAGNAR HRKAN RENDAHL.

v MEANS FOR PRODUCING ELECT RICA L OSCILLATIONS. APPLICATION FIL ED MAR. 18, 1909. RENEWED JAN. 8.1911.

lfilfifi fi. v I Patented Feb.20,1917.

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GEORG GRAF ARCVO & RANA HRKAN RENDAHL. MEANS Fi'JR PRODUCING ELECTRICAL OSCILLATIONS. APPLICATION FILED MAR. 18, I909. RE'NEWED JAN. 8.1917- Patent-ed Feb.20,1917.

4 SHEETS-SHEET 2- avezziar 7 GEORG GRAF ARGO & RAGNAR HRKAN RENDAHL.

MEANS FOR PRODUCING ELECTRICAL -OSCILLATIONS. APPLICATION FILED MAR-18,1909- RENEWED JAN. 8.1917- Patented Feb. 20, 1917.

4 SHEETS-SHEET 3.

GEORG- GRAF ARGO & RAGNAR-HRKAN RENDAHL.

MEANS FOR PRODUClNG ELECTRICAL OSCILLATIONS. APPLICATION FILED MAR.I8,1909.R ENEW EDV JAN. BUQIL! mmwa. PatentdFeb. 20, 1917.

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means roia rnfonucme nrpcra rcarj oscrttarroirs.

p fl i o te s test Patented Feb. 20, Wilt.

Application filed March 18, 1909,5eria1N0. $84,217. Renewed January-8, 1917. eriaI No. 151L838.

ducing Electrical Oscillations, or which the following is a specification.

Our invention relates to a method of producing rapid, and but very slightly damped electrical oscillations, particularly for use in radio-telegraphy, and a primary object is to provide improved means for carrying the same into practice.

The methodconsists in exciting an oscil-- latory circuit which contains no spark-gap, and consequently has only a small damping action, from another oscillatory circuit which contains a spark-gap of very small width, as,a rule less than '0. 5 n un. in air for example between two a,d]o1n1ng termlnal plates, and correspondingly more or less in'other dielectrics, such as hydrogen for example. Such short gaps are called in the art quenched spark gaps, for the reason thatthe spark is quenched .very rapidly therein.

It was found that such an arrangement had the advantage that, even when the circuits were coupled with one another fairly closely, the usual, relatively highly damped,

coupling waves did not occur at all or only for a short time. On the contrary, practically only one wave was produced which corresponded to the fundamental oscillaof parall tion and natural damping of the secondary circuit, so that after a short time the .p'ri

mary' circuit, containing the spark-gap, could be looked upon as non-existing.

p In spiteof this advantage, however, this method could not be employed in practice heretofore, an the one hand because no energyworthmentioning could be converted,

, and, on the other hand, on account of the rapid destruction of the spark-gap termi nals and the great inconstancy of the oscillations produced thereby.

Now in accordance with the present inventionwe do. away with these defects in the firstlace by making the, spark-gap cl plates or disks of good heatconducting metal, having a coeficient of conduction of heat at least equal to. that of gold, such as copper or silver, or alloys' modified form of such a column which contain these metals as their principal constituents. The electrodes may also be made of other suitable material, adapted for the mechanical requirements, having only the operative faces coated with copper or silver. The coatings must be as uniform and plane as possible, and it is preferable to apply them as sheet metal by rolling or soldering. Preferably, before the soldering operation, holes are drilled in the supporting plates or disks, through which the gases generated during the soldering operation can escape.

In order that our invention may be clearly understood reference will be made to the accompanying drawings in which several embodiments are represented diagrammatically by Way of example, and in which .Figure' l is an elevation partly in section of a spark-gap consisting of parallel plates or disks in a box, Whereas Fig. 2 is a like view of a spark-gap, whose plates or disks consist, for example, of brass provided with a coating of copper or silver;

Figs. 3, 4, 5 and 6 are vertical sections of other modified forms of spark-gaps,

whereas Fig. 7 is a like view of a series sparkgap, and

Figs. 8 aud t? are like views of improved series spark-gaps'in the forms of columns, the inclosing box being entirely omitted or. only partially shown in Figs. 3' to 9 inclusive;

FigsylO and 11 are longitudinal elevation partly in section and transverse section respectively of a series spark-gap column provided with coolers, and

Figs. 12 and 13 are, longitudinal and transverse sections respectively through a provided with coolers, whereas 4 Fig. 1 1 is an elevation ofpart of a series spark-gap column provided with cooling ribs;

Fig. 15 is a sectional elevation of a sparkgap short-circuiting device, whereas Figs. 16 and 17 are side and end elevation respectively of another for-m of sparkgap 'short-circuiting device according toztheinvention; I

Figs. 18 and 19 are diagrams of cur ent curves clearly, explained hereinafter;

Figs- 20 and 21 are front sectional elevatidn and transverse section respectively showing parts of an improved alternating current generator, whereas Figs. 22 and 23 are diagrams of connections of radiotelegraphic systems fed by al ternating current generators in accordance with the invention, the series spark-gap in the diagram 23 being shown in vertical section. Referring to the drawings and firstly particu'larlyto Figs. 1 and 2, (1, indicates the electrode plates, 6 the box containing the same, ca screw movable in the box and attained when all air is prevented access to 25 the gap, apparently amongother reasons because the electrodes then oxidize only coniparatively slowly. Accordingly, an im-- proved form of the invention is one in which the electrode plates are pressed against each other, andare kept at a definite distance apart by insulating intermediate layers, and

in which the spark chamber is closed quite air-tight or as nearly so as possible.

Fig. 3 represents by way of example one constructional form of such a spark-gap. In

this figure a indicates the electrodes, e a ring of insulating material, for example mica or press-spahn which closes the spark chamber 72. air-tight, f denotes part of a box or clamp connected with the bottom electrode, g the screw of the clamp which presses the top electrode toward the bottom. The ring e serves simultaneously as a spacing insulator for keeping the electrode plates at a definite distance from one another, so that such distance is retained as uniform as possible over the entire surface. I The constructional form according to Fig. 3 has, however, still the disadvantage that the insulating material may be destroyed by the sparks, whereby injurious products of combustion remain in the spark chamber and the device is rendered inoperative after a few minutes. 7 This disadvantage is overcome by making the distance between the electrodes greater at the edges of the insulating material than in the spark chamber, whereby the insulating material is protected from being o burnt. Gonstructional forms of such an arelectrodes. In Fig. 5 like reference characbut the groove 2' is formed by suitably shaping one electrode a, as clearly shown."

In all constructional forms *it is essential that all sharp edges be avoided. Further, it is very important to increase somewhat the distance between the electrodes in the central. part of the gap, so that the spark chamber becomes annular. In contradistinction to the increase in distance between. 5 the electrodes at the edges of the insulation, this increase in the center does not require to be very considerable and may be made, for example, by grinding withemery. In the case of very large spark-gaps it.,is prefg erable not to sha e the electrodes as disks but as rings, as clearly shown in Fig. 6.

A simple spark-gap as described above with reference to Figs. 4: to 6 permits of the production of a considerable oscillatory 5 energy with certainty of working. This, however, soon reaches a limit which is occasioned by electrical and practical reasons, so that as a rule a transmitter operating together with the spark-gap would scarcely 9o exceed a range of 50 to kilometers, which, asis well known, would not suffice in Practice for radio-telegraphy.

11 order to increase the energy converted into oscillationsbeyond these limits, according to additional embodiments of the present invention a plurality of spark-gaps of the character described aboveare connected in series.

Fig. 7 shows such a connection in which three spark-gaps of the form shown in Fig. 3 are shown connected in series. Fig. 8 shows another constructional form in which the electrode disks a are superposed and pressed together by means of .one single screw 9, whereby a considerable savin in space and simplicity in working is obtained when a large number of partial sparking distances are employed. Preferably the electrode disks a are of equal size and the rings e equally thick, so that a uniform distribution of the entire tension is obtained among the individual sparking distances.

Fig. 9 shows a further improvement which consists in the two sides of all the disks a, with the exception of the two outermost, being utilized as operative electrodes.

Whereas in simple spark-gaps the heat produced by the sparks can sufficiently flow away directl this is not the case with the inner plates of a series spark-gap and therefore they become unduly heated. To avoid this, according to the invention coolers are .employedwhich are either arranged between the electrodes or, m somewhat small constructional' forms, are: connected as cooling ribs with the electrodes. v

Three constructional forms of such an arrangement are illustrated by way of example in Figs. 10 to 14. Referring firstly to Figs. and l1,-coolers It are arranged be tween the outer faces of the electrodes (1. in

disks of good heatconducting material which take up the heat of the electrodes by conduction and radiate it into the air; For the latter purpose theydpossess 'a larger diameter than the-electr es a so that the en tire aggregate has the'appearance of a radiator well-known in .the art of heating.

' In the constructional form according to Figs. l2 and 13 the coolers is are made hollow for holding a cooling'liquid', such as water for example; For this reason they do not need to project beyond the edge of the electrodes,;since the heat is withdrawn from the cooling liquid by circulation or, as indicated in the example illustrated, by evaporation. It is to be understood that the device may also be. cooled by a gaseous agent instead of by liquid means.

The construction of the columns comprising electrodes, spacing insulating rings and coolers is so arranged according to the prescut invention that it is readily possible t5 exchange individual elements, their correct positions relatively to the other elements being simultaneously assured. 'For this purpose, in the constructional form shown in Figs. 10 and 11 the electrodes a, and in the constructional form shown in Figs. 12 and 13 both the, electrodes 0 and the coolers 71:

rest on two insulated rods Z which extend the entire'lengths 'of the columns; in the former example these rods pass through corresponding holes in the coolers, and are attached to the end plates Z and Z, and to-' gether with these constitute the frame of the spark-gap. By means of the clamping V screw 9 movable in the top plate the disks,

spacing rings and coolers can be pressed together 51nd held in position between the screw and the bottom plate.

In order to make it still more certain that the spark-gap will be assembled correctly, in the form shown in Figs. 10 and 11 there is arranged above the electrodes a a third rod m which, when electrodes are to be exchanged, can be turned up around a pivotn provided in the bottom plate. For this purpose, instead of a hole a slit is provided in the coolers k for this rod, as clearly shown in Fig. 11. In the form shown in Fig. 12, there may be provided above the electrodes two rods we placed so far from one another that the elements between them can be lifted out. In the form shown in Fig. 14 each of the electrodes is provided with a cooling rib a as clearly shown.

ln another modification according to the invention the series spark gaps just described above are provided with a short-cir:

, cuiting device by means of which one or more partial sparking distances canbe shortnew .' circuited'at will. For example, itit is 'de- I sired to-work alternately with conerer or this form these coolers are made as solid;

detectors for instance. those of the elecfor working with thecoherenf all the sparking distances and thereby obtaining a 'few .discharges of high potential, whereas for workingwith a detector apart is short-cit. culted and thereby frequent discharges are obtained with the same charging voltage.

-trolytica1 or rectifying type, this is possible accordin to the present invention by using,

Another constructional form of short-circuitin'g device which is particularly suitable for testing purposes is represented by way ofexample in Figs. 16 and 17. 'ln-these'figures q denotes a block of insulating material having an insulating handle 79. On the block are mounted two metal strips r which extend transversely to the block as shown in Fig. l7,'and into which are screwed micrometer screws 8. with their points facing one another so that the distance between the points can be varied and measured. With the metallic strips 1' there are electrically con nected elastic zcont'act clips or hooks 0, insulated from each other by block. 9, which are shaped and arranged in such manner that. they can be thrust between'the electrodes a, the gap between which is to be tested. The spark-gap is then formed between these points from a certain distance between the points, of the screws onward so that from the distance between-the points at which the spark first- 26cc ;rsthelgngth of" the spark-ga 'betwe it? tested electrodes at can be con'c ude'd' N ow the series spark gaps hereinbefore described with reference to Figs. "7 to 14 admit of a much greater energyof oscillation being emitted than a simple spark-gap according to the forms shown in Figs. 1 to 6. But here also a limit is soon reached owing to the practically admissible tension at the transmitter. Since, as is known, the energy converted into oscillations per second is expressed by the formula 'mCV minative for the length of the waves which are to be emitted, and accordingly can be increased only within narrow limits, it would have seemed quite obvious, in order to obtain a large n, 2'. e. in order to obtain as great a now be described to complete the disclosure, though this subject matter has been dedischarge as possible, to employ a direct current'for feeding the arrangement. f We have however found that direct. current" feeding has considerable disadvantages. After a short time the spark tends to occur at all times at the same portion of the electrodes, which'are thus rapidly destroyed whereby the entire arrangement is soon made inoperative. Also the time interval between the sparks is by no means regular.

A further object of the invention is to remove these defects, by supplying the spark gaps described before with alternating 'cur-' rent. The alternating current may be supplied in this instance by an alternating currentgenerator, the current of which is either directly or indirectly, by means of atransformer, conducted to the spark gaps, or also it may be supplied throiigh the secondary coil of a transformer, the primaryvcoil of which is supplied with pulsating direct current, The explanation of the advanta-' 'geous behavior .ofthe spark-gap with al-' ternating current feedin may be found in the fact that thespar is continuously compelled to use new places for jumping across. In practice, indeed, the electrodes look quite different according as they .are

scribed and claimed in my co-pending application Ser. No. 652,018, which is divided from the present a plication.

If a telephone an an integrating detector are'employed at the receiving station, according to the working conditions of the transmitter in each case there are the following possibilities Uase 1.The feeding arrangement is so tuned in known manner that only one spark for several alternations is produced for instance by reducing the charging voltage. The tone which is perceived does not differ from that which has been perceived with the.

spark-gap used heretofore.

Oase 2.The apparatuses are so adjusted that exactly one spark is produced for each alternation. The' tone which is perceived 1 now corresponds to the periodicity of the 60- machine. y

Case 3.-The apparatuses are so adjusted that several, but still few, sparks per alternation are produced. As incase 2, the tone of the feeding machine is perceived. It is, however, accompanied by extrafious noises i iicp'as" whichlproceed from the irregular sequence of the sparks during each period.

- Uaae 4.-,An exceedingly large number of sparks are produced er alternation. Here again, as in case -2,-t e tone of the feeding machine is perceived. But the extraneous noises are less noticeable than in case 3.

It is seen from the above that the possibility exists of perceiving at the receiving station the tone of the feeding machine instead of the noises perceived heretofore which are very.v similar to those due to atmospheric disturbances. Now a further feature of our invention consists in so selecting the frequency of the feeding machine that in the receiver at the receiving station the tones having about 400 to 3000 vibrations per second are produced which are easiest perceptible by the human ear.

In the case of long spark-gaps known 35 heretofore the employment of alternating current of such high frequency would have been disadvantageous, indeed impossible, as the spark would have soon become inactive. This could only be avoided by employing'a blast magnet, an air blast 'or' rotating electrodes. These, however, still further .reduce considerably the already .very low efliciency, i. e. the ratio between the primary energy of the machine and the energy which is to be emitted, which amounts to at most 20%, whereas an efiiciencyup to 70% can readily be obtained bythe means according to the present invention.

producing a musical tone in the rece1ver the important advantage of practicallykzo'mplete freedom from disturbance in working wireless stations is obtained, both with regard to other stations and also with regard to atmospheric discharges. The tone,1o5

- in the telephone at the receiving station is easily perceived by the ear even when of ve weak lntensity, and contrasts distinctly wit the noises produced by disturbances, in

like manner, for example, as the sounds of human speech contrast with microphone extraneous noises in telephony. In this manner several wireless stations, which are tuned to the same high frequency, can be worked independently and free from dis- 116 turbance by one another by means of transmitters which are tuned to different acoustic pitches. The capability of selection afforded hereby can'also be carriedstill further by means of telephone 'diaphragms 120 tuned to a definite pitch, by means of other monotonic acoustic resonators, or by means of oscillating systems tuned to definite periods and the like, electrical and acoustic tuning being able to be combined simultane- 0115 y.

If it is wished to produce a musical tone and simultaneously emit large quantities of energy certain difiicultics are met with. The aboye mentioned best method of producing (case 2 one spark per alternation) adniits of the energy being increased to only a certain limit, from which point onward lid , a tepure tones are produced;

inadmissible tensions would occur. number of sparks per'alternation can indeed be increased considerably (case 4), but with the disadvantage that the loudness ot the sound at the receiving station would be in no relation to the increase ,of energy at the transmitting station. p

Fig. 18 shows the distribution of the sparks for this case. ,The sparks are indicated by the alternatelyupwardly and downwardly directed vertical lines. It is seen that the sparkless pauses y between two discharging periods 00 are only short. 011 at:-

lcountg ot .theseyshort sparkless pauses, from the telephone d1aphragm has no time to vibrate back into its normal position. The consequence of this is that the maximum amplitudes of the vihr'atiiig dia-' phragm do not become so great as might-be which is brought by the sparks during the time a: outof its normal position to'vibrate back into its initial position, so that the subsequent sparks can act afresh on it- A generator particularly suitable for use v in carrying into practice the present invention is illustrated by way of'example in Figs. 20 and 21. The former figure shows a claw-field generator in front sectional'elevation and the latter. is a transverse section of the rotor only. V indicates the stator. The rotor '0 has only one single winding 2%, which is arranged within two halves "0, '0 of the rotor keyed on the shaft u, and, further, at its periphery a series of claw-like poles to overlapping the winding and situated alternately on the one and the other half of the rotor. This arrangement, which is known in itself, has the advantage of a specially favorable construction and admits of a very high speed bein obtained. In the construction used hereto ore the distance between the individual claws was approximately equal correspondin to the desired sine curve. The stray fiel between the individual claws was therefore very great so that the efiiciency of the machine was thereby very much impaired and the'above mentioned advantages were canceled.

. garages According to our present invention the rotor is so constructed that the distance between the claws w corresponding to the form of curve according to Fig. 19 is at least twice as great as the breadth of the claws.

The stray field losses are thereby reduced to a fraction of the previous amount, with out the advantages of the: resent construction being diminished. ere difliculty is encountered in obtaining a singlephase alternator of the desired high frequencies current generator of the ordinary commercial frequencies may be used. When threephase current is employed .for example, a periodicity three times as high can be produced and, accordingly, with a given pitch above referred to, a multiphase alternating of the note of the recelver, a periodicity ofconnected the second and third oscillatory circuits provided with the condensers C and G and the spark-gaps 1F and F respectively. By means of the coils S and S the oscillations of the three primary circuits are transmitted to the secondary system which consists, for example, of the antenna A. and the earth connection B.

The primary system consisting. of the three oscillatory circuits receives during one period of thegenerator three impulses, so that a periodicity three times as high is generated in the secondary circuit.

Further, this arrangement-has the advan- 'tage that the individual sparkgaps are loaded'less than when a singlephase generator havi a periodicity three times as high is crap oyed. Moreover an actual musical tone is produced in the receiver if care is taken that the above described conditions are fulfilled under which the oscillations are produced in the desired frequency equal to the pitch of the tone desired; 0n the other hand it is possible, by increasing the number of sparks per phase, to obtain a practically noiseless transmitter, just as if direct current were employed, but with the difi'erence that, with regard to the con stancy of the oscillations and the quantities of energy, it has all the advantages of the alternating current.

Referring now to Fig. 23, the entire arrangement of a system for radiotelegraphy is here represented, the previously described means being employed therein. In this figure 2 denotes a claw-field generator of high periodicity which gives a current curve cor.- responding to that shown in Fig. 19; 1 denotes a variable inductive resistance, 2 a

Horse keyand 3 a transformer. The circuit comprising these arts 2, 1, 2 and 3 serves and the spark-gap 8 a closed oscillation cir-' .for feeding the h1gh frequency system. In

this latter system 4 d which forms withthe self-induction coil 5 011%, with which the antenna circuit is associated. The remaining details of the general arrangement have already been described above.

While we are aware that with respect to the features ofour new spark gap, certa1n I individual features or elements thereof may be known in the art, we claim that the merit of" our invention resides principally in the discovery that certain groups of metals, characterized by their heat conductivity, as active electrodes of the so-called quenched gaps employed inthe shock excitation method, as well as the sha e of the electrodes and their manner 0 assembling as set forth more particularly in the annexed claims,.have rendered this method of producing powerful oscillations commerciall practicable, whereas heretofore while this method was known in the art, it was impracticable for such commercial use for the,

" reasons stated hereinbefore.

shock excitation method, a short, quenched spark gap, comprising'a plurality of parallel electrodes,'the active faces of said electrodes being composed of a good heat conducting metal, having a coefficient of heat conduction at least equal to that of gold.

3.'In an arrangement for producingslightly damped electrical oscillations by the shockexcitation method, a short, quenched spark gap, comprising a plurality of plates forming the electrodes of the gap, the active faces of said plates being composed of a good heat conducting-metal, having a coefficient of heat conduction at least equal to that of gold.

4. In an arrangement for producing slightly dampedelectrical oscillations by the shock excitation method, a short, quenched s ark ga comprising a plurality of electi'bdes, th e active faces of said electrodes being composed of silver.

5 In an arrangement for producing slightly damped electrical oscillations by the shock excitation method, a short, quenched spark gap, comprising a plurality of parallel enotes a condenser,"

silver.

or producing being composed of-silver.

6. In an arrangement for} producing sl ghtly damped electrical oscillations by the gap, comprising a plurality of plates excitation method, a short, quenched spark forming the electrodes ofthe-gap, the active faces of said electrodes being composed of 7; In' an arrangement for producing slightly damped electrical oscillations byv the shock excitation method a'short, quenched spark gap, comprising a plurality of electrodes, the active faces of said electrodeslbeing composed of good heat conducting metal,

having a. co-efiicient of heat conduction at least equal to that of gold, and means for I hermetically sealing the sparking area of said electrodes.

8. In an arrangement .for producing slightly damped electrical oscillations by the,

shock excitation method, a short, quenched spark gap, comprising-a plurality of plates formingthe electrodes of the gap, the active faces of said plates being composed of a good heat conducting metal, having a coeflicient of heat conduction, at least equal to that of gold, and means for hermetically sealing the sparking area of said electrodes. In an I arrangement for producing slightly damped electricaloscillations by the shock excitation method a short, uenched spark gap, comprising a plurality 0 parallel electrodes, the active faces of said electrodes being composed of a good heat conducting metal, having a coefficient of heat conduction at least equal to that of gold, and means for hermetically sealing the sparking area of said electrodes.

10. In an arrangement for "producing slightly damped electrical oscillations by the shock excitation method, a short, ,quenched spark gap, comprising a plurality of parallel plates forming the electrodes of the gap, the active faces of said plates being composed of a metal having a coefiicient of conduction of heat at least equal to that of gold, a spacing insulator arranged between said plates for determiningthe width of the gap between the same, and clamping means for holding I said plates and insulator together.

11. In an arrangement for producing slightly damped electrical oscillations by the shock-excitation method, a short, 'uenched spark gap, comprising a plurality 0 parallel plates forming the electrodes of the gap, the

active faces of said plates being composed of a metal having a coefficient of conduction of heat at least equal to that of gold, a spacing insulator of uniform thickness arranged between said plates for determining the width of the gap between the same, and clamping means for firmly holding said plates and insulator together under pressure,

I ma as air-tight re ease 1 s armaemteris obtained;

12. In an arrangement for producing i slightly damped electrical oscillationsby the plates for determining the' Widthof 'thegap,

shock excitation method, a" short, quenched spark gap, comprisingplurality of parallel plates forming the electrodes er the gap,

the active faces-of sai'd plates being composed of a metal havin a coeficient of conduction of heat at least equal to'that of gold, a spacing insulator arranged between said between the same, and clamping means for holdingv said plates and insulator together, the distance between said plates the'edges of the'insulator being greater than the Width of the'ga'p which it determines.

.13. In an arrangement for producing slightly damped electrical o'scillati'oiis by the,

nite distance apart, the shape of the active faces of said plates being; such that the sparking space'betw'een the same is annular. 7 14. In an arrangement, for producing slightly damped electrical'oseillations' bythe shock excitation method, a series of quench" spark gaps, comprisinga plurality of" gap electrodes having their active faces com posedof ametalhav'ing a coeflieientj of heat conduction at least equal-to thatof gold.

'15. In an arrangement for producing slightly'damped eleetri'caloscillations by the shdck excitation method, a series of quench spark gaps,'comprisjing a plurality ofelectrodes having their active faces parallel .to'

each other' ahd being composed'pf a metal with'acoeiiicient' of heat conduction at least equal to thatof gold, said'electrodes formiug the'electrodes' of the spark Whichthe series gap'iscompos 16. 111 an" arran ement for producing ap units of 3, a

' slightly damped electrical oscillations by the shock excitation'me'thod, =a series'of quench spark gaps, coinprisiug' a'plurality of electrodes havin their active facesc'omp'osed of silver,'s'aid electrodes forming the electrodes of the spark gap units of which the seriesgap is composed.

17. In an" arrangement for' producing slightly damped electrical oscillations 'by the shock excitation'method, a series'of quench spark gaps, comprising a plurality of paralleldisk'sof ametal, havinga coefficient of conduction" of' heat at leastequal to that gap units of Which'the series: gap is'co posed," insulating spac ng rings arranged one between each adjaceiitpairof disks'for said rings air-tight together.

determining at were of] each gapunit an draping" means for holding said disks and said ringstogether.

181111 an arrangementfer produeing slightly damped electrical oscillations by the shock excitation method, a series of quench spark 'aps', comprising a' plurality of p'aral le'ldis is of a metal, having a coefficient of heatcondueti'vity at least equal to that 9f gold, forming the electrodes of spark gap units of which theseries gap is composed,

insulatingspacingrings arranged one h etween eaeh' adjacent pair of disks for determin ngthe width of each gap unit and clamping means for holding said disks and 19.111 an arrangement for producing slightly damped electrical oscillations'by the shock excitation" methed, a series of quench spark gaps, comprising a plurality of paral-' lel' disks of a metahhaving a coeficient 0? 'heatconduetivity at least equal to that or a gold, -'.for'm1ngthe electrodes of spark ga un1ts,';of which the series gap is composed,

insulating spacing rings arranged one between each adjacent pair of disks for determining the Width of each ga'p clamping means for holdin "said disks and unit, and

said insulators together, t e distance between'the electrodes at'the edges of the insu-' lators being greater-than the width of the gap space. Y I

- 20. ln an arrangement for producing slightly damped electrical oscillations by the shock excitation method, a' series of quench spark gaps, comprising a plurality of pan ,allel disk's of a rhetal'hav'ing a coefficient of conduction of heat; at least equal to that of gold, forming the electrodes of 'Which the series'ga'p is'comp'osed, a cooling rib'connected with each disk, insulating spacing rings arranged one between eachadjaeent pair of disks for determining the-width of each of said units, and clamping means' for holding sald' disks and said rings together.

21. In an arrangementfor producing slightly damped electrical oscillations by the shockexcitation method, ase'rieso'f quench spark gaps, comprising a plurality of parallel disksof a metal having a coflieient' of conduction of heat at least equal to that of gold, forming the electrodes of spark gap units of which the series gap is composed, a' cooling disk-shaped plate composed of a good heat conducting metal contacting. with, Y

disk, insulating spacing rings arranged one" and extending beyond the periphery of each between each adjacent pair ofi disks for determining the width'of each of said units and clamping means for holding'said disks and said rings together. y p

22. In an arrangement fol" producing slightly damped electrical'oscillations by the shock excitation method, a; series of short h s 5.gaff -'u n1 ts' of; which the series gap is com gaps comprising a pluralit eli-Hisks o .a metal having a coefii nduction of heat at least ual to old-,'- forming the electrodes 0 spark posed; insulating spacing rings arranged one I qbet weeneach adjacent pair of disks for determiningthe width of each of said units, andclamplng means comprising a base plate,

a top plate, a plurality of insulated rods slightly damped electrical oscillations by the shock excitation method, a series of quench spark gaps, comprising a plurality of parallel disks of metal, having a coeificient of conduction of heat at least equal to thatvof gold, forming the electrodes of spark gap units of which the series gap is composed, a cooler connected with each disk, insulating spacing rings arranged one between each adj acent pair of disks for determining the width of each gap unit, and clamping means comprising a base plate, a top plate, a lurality qf insulated rods carrying said e cotrodes and passing through said coolers, attached to said plates, and a screw movable in said topwplate for clamping said disks and rings together and against the bottom plate, asset forth.

24. In 'anarrangement for producing slightly damped electrical oscillations by the shock excitation method, a series of quench spark gaps, comprising a plurality of parallel disks of. a metal having a coeflicient of conduction of heat at least equal to that of gold, forming the electrodes, of spark gap units of which the series gap is composed, insulating spacing rings arranged one between each adjacent pair of disks for determining the width of each gap unit, clamping means for holding said disks and said rings together, and means temporarily attachable to the series spark gap for temporarily. short-circuiting a gap unit in the same. y

'25. In an arrangement for producing slightly dampedelectrical' oscillations by the shock' excitation method, a short, quenched sparkjgap comprising a plurality of parallel plates forming the electrodes of the gap,

the active faces of, said plates being composed of a metal having a coeflicient of con-- duction of heat at least equal to that of gold, a spacing insulator consisting of mica arranged between said plates for determining the width of the gap between the same, and clamping means for holding said plates and insulator together.

26.,In' an arrangement for producing slightly damped electrical oscillations by the thickness arranged between said plates for determining the width of the ga between the same, and clampin means or firmly holding said plates an insulator together under pressure, whereby an air-tight spark chamber is obtained.

27. In an arrangement for producing slightly damped electrical oscillations by the shock excitation method, a short quenched spark gap having a plurality of electrodes whose faces are suitably shaped to form oppositely disposed parallel annular sparking areas, the distance between said areas representing-the shortest distance between said electrodes throughout.

28. In an arrangement for producing slightly damped electrical oscillations by the shock excitation method, a short quenched spark gap comprising a plurality of electrodes having their active faces parallel to each other, a spacing insulator arranged between said electrodes for determining the width of the gap between said faces, the dis: tance between said electrodes at the edges of the insulator being greater than the width of the gap which it determines.

29. In an arrangement for producing slightly damped electrical oscillations by the shock excitation method, a short quenched spark gap comprising a plurality of parallel plates forming the electrodes of said gap, the shape of the activefaces of said plates being such that the sparking spaces between the same is annular.

30. In an arrangement for producing slightly damped electrical oscillations by the shock excitation method, a short, quenched spark gap having parallel electrode faces, each face having a central and a peripheral recess registering with the corresponding recesses of the face of the co-acting electrode.

31. In an apparatus for producing powerful electrical oscillations, a plurality of electrodes arranged in series and spaced apart from each other "to form gaps therebetween, and means located out of contact with the arcing surfaces of the electrodes for maintaining the gaps between adjacent electrodes air-tight.

32. In an apparatus for producing powerful electrical oscillations; a plurality of metal electrodes spaced apart from each other to form spark gaps therebetween, and means interposed between adjacent electrodes but located out of contact with the arcing surfaces thereof for rendering the air gap spaces air-tight.

33. In an apparatus for producing powereral edges of adjacent disks or plates and ful electrical oscillations, a plurality of out of contact with the arcing surfaces theremetal electrodes of extended surface area, of to determine an air gap and render the air 1 I placed the one upon another, and means ingap space therebetween air-tight.

5 terposed between adjacent electrodes but 10- In testimony whereof, we afix our signacated out of contact with the arcing surfaces tures in the presence of two witnesses.

thereof for rendering the spark gap space GEORG -GRAB G therebetween air-tight. V

34. In an apparatus forproducing power- RAGNAR HKKAN YRENDAHL' 10 ful electrical oscillations, a plurality of disks Witnesses:

or plates, superimposed one upon another, WOIDEMAR Ham, and means interposed between the periph- HENBYHASPER. 

